Black May (Thai: พฤษภาทมิฬ; RTGS: Phruetsapha Thamin), also known as "Bloody May", was a series of mass protests and subsequent crackdowns by security forces and police in Bangkok in May 1992.

A rally of over 200,000 people led by Chamlong Srimuang was held on 17 May, caused by the extending of the military regime of Suchinda Kraprayoon, the 1991 Thai coup d'état leader.

The coup-makers of Class 5, who called themselves the National Peace Keeping Council (NPKC), appointed Anand Panyarachun as prime minister.

The NPKC desired to dominate Thai politics as it established Samakkhi Tham Party (STP) in April 1991.

Narong Wongwan, STP leader, was designated prime minister, when media alleged that the United States had refused him entry admission due to the suspection of involvement in drug trafficking.

[5] Chamlong began his hunger strike on 5 May and vowed to die in one week if Suchinda did not step down, shortly he became the lead figure of the protest.

[6] On 9 May, Suchinda responded by saying he would support a constitutional amendment making individuals who had not been elected to parliament ineligible for the premiership.

[7] Air Chief Marshal Kaset Rojananil, head of the National Peace Keeping Council and General Isarapong Noonpakdee, head of its subsidiary the Bangkok Peacekeeping Council warned protesters not to attend the rally alleging support from ill-intentioned persons.

[8] Before the third round of demonstrations, the Confederation for Democracy (CFD), an oppositional alliance against the military-sponsored government of Suchinda Kraprayoon was formed, mainly led by Chamlong Srimuang who just resigned from the leadership position of Palang Dharma Party,[3] Prinya Thaewanarumitkul of the Students Federation of Thailand, slum-dwellers' activist Prateep Ungsongtham, the daughter of the now-incarcerated Chalard Worachat, trade unionist Somsak Kosaisuuk, politician Veera Musikapong, and academics Sant Hathirat and Weng Tojirakarn.

On Sunday, 17 May, the two leading government parties announced that although they supported the constitutional amendment, they also favoured transitional clauses that would permit Suchinda to serve as prime minister for the term of the parliament.

[10][13] At about 20:30, Chamlong, Sudarat Keyuraphan, and Sant Hatthirat led the protesters on a two-kilometre march to the Government House to demand Suchinda's resignation.

[14] The protesters were halted at Phan Fa Lilat Bridge, which had been barricaded with razor wire by the police.

At 11.00 pm, a group of demonstrators attempted to break through the barricade, but were repulsed by water cannons from four fire trucks blocking the way.

The protesters then tried to take over two of some ten fire engines stationed nearby,[15] but were beaten back by riot police armed with batons and shot by water cannons.

[10] Government buildings and police vehicles were set on fire, a "third party" was involved in initiating violence on Phan Fa Bridge, according to Chamlong.

Early on the afternoon of 18 May, Suchinda publicly accused Chamlong of fomenting violence and defended the government's use of force.

The army fixed bayonets at 9.30 pm, caused some demonstrators to raise their arms in confrontation to dare the forces to shoot.

There were reports of gunmen shooting protesters in various areas in Bangkok,[20] presuming to be the Royal Thai Police official.

[20] When government troops secured the area around Phan Fa Lilat Bridge and the Democracy Monument, protests shifted to Ramkhamhaeng University in the east of the city.

[25] The New York Times dubbed the events as the bloodiest popular uprising in the modern history of Thailand,[6] only to be replaced by the 2010 Thai political protests.

[26] On 23 May, King Bhumibol signed Suchinda's amnesty decree that applied to both side of a conflict, with the reason to protect the security and unity of the country.

Kaset Rojananil, Supreme Commander of the armed forces and director of the National Peace Keeping Council, stated that the army and the police shot protesters in the lower part of the body only.

Suchinda was later appointed chairman of Telecom Asia (today known as True Corporation), a company which received a concession to install two million telephone lines in Bangkok during the Anand Panyarachun government.